1. Field of the Invention
This invention relates to ethylene/vinyl acetate/isobutylene (EVAI) terpolymers, methods of producing such terpolymers and their use in hot melt coating processes.
2. Description of the Prior Art
Saturated hydrocarbons such as cyclohexane, butane, propane, etc., have been used to increase the melt index of ethylene/vinyl acetate (EVA) copolymers. Such materials, however, simultaneously increase melt index and stiffness, the stiffness of the resins being increased to such an extent that it is difficult to process such resins in hot melt solutions.
U.S. Pat. No. 3,433,573 Holladay et al discloses forming polyblends containing from 5% to 95% by weight of an EVA copolymer and crystalline polymers obtained from 1-olefin monomers of from 3 to 8 carbon atoms, particularly polypropylene polymers. The EVA polymer contains from 5 to 35% vinyl acetate (VA). Materials such as polybutene-1 can be used in forming the polyblends. Blends having a broader stiffness range are obtained which provide low modulus rubbery products of excellent flexibility which can be used to manufacture transparent films for wrapping and packaging purposes.
U.S. Pat. No. 3,544,662 Polestak et al. discloses forming high melting point polymer compositions comprising a 3-methyl-1-butene polymer or copolymer where the copolymeric constituent can be 1-butene. No disclosure of EVA copolymers is set out.
References disclosing polymer compositions known to the art include U.S. Pat. Nos. 3,111,500 Bartl et al., 3,277,210 Mirabile et al.; 3,487,129 Platzer and 3,544,660 Thomas et al.